through May, it was possible to delimit areas 

 of environmental resistance and induction. 

 These areas were then considered for various 

 years along with the records for winter and 

 summer albacore catch records. The area was 

 then classified by two basic patterns. In the 

 first, the warmer waters are inshore; in the 

 second, the cooler waters are inshore. 



From the data presented, it is concluded 

 that if the winter fish are concentrated in two 

 or three pools from which they move southerly 

 to form a single congregation during the sum - 

 mer close to Japan, good catches of summer 

 albacore may be expected. Concentrations of 

 winter albacore in the eastern portion of the 

 area, or lack of definite concentrations, result 

 in a poor summer catch of albacore. 



volumes were highest to the east. There was 

 little seasonal difference in food volumes. Reef- 

 associated organisms appeared most frequently 

 in the diet of albacore caught near land. 



Troll-caught albacore in the North Pacific 

 fed, prior to capture, throughout the day, but 

 evidence for distinct feeding periods was not 

 clear. Evidence is presented that albacore also 

 feed at night. The higher stomach content vol- 

 umes of troll-caught albacore occurred in waters 

 of mid-clarity. Some competition for food may 

 exist among albacore, yellowfin, andbigeye tuna 

 in the equatorial Pacific. 



Checklists of the organisms identified in 

 stomach contents show the number of such organ - 

 isms, their frequency of occurrence, and aggre- 

 gate total volume. 



Iversen, Robert T. B. 



Food of albacore tuna, Thunnus germo 

 (Lacepede), in the central and north- 

 eastern Pacific. ^Conference Paper 

 VII - 107 



The stomach contents of 544 albacore 

 tuna, Thunnus germo (Lacepede), captured in 

 the central and eastern North Pacific during the 

 years 1950-57 were analyzed to: (1) identify the 

 organisms eaten; (2) determine if the abundance 

 and distribution of albacore is related to the 

 abundance and distribution of their food; and (3) 

 relate feeding to size, method of capture, geo- 

 graphic location, season, distance from land, 

 time of day, and water clarity. The albacore 

 were captured by longline, gill net, and troll. 



Stomachs of the larger albacore contained 

 more food than smaller albacore, but the larger 

 albacore contained less per pound of body weight . 

 Stomach contents consisted mainly of a variety 

 of fish, squid, and crustaceans, the percent vol- 

 ume of each differing according to the method of 

 capture. 



Johnson, James H. 



Sea temperatures and the availability of 

 albacore (Thunnus germo) off the 

 coasts of Oregon and Washington. 

 /Conference Paper V - bj 



Wide variations exist in landings of alba - 

 core in Oregon and Washington. In 1944, Oregon 

 and Washington landings reached 34 million 

 pounds but dropped to 0. 6 million pounds a decade 

 later. Variations in landings may be a result 

 of fluctuations in availability. Investigators 

 have shown that distribution of albacore along the 

 North American coast is influenced by sea tem- 

 peratures. Although weather conditions and 

 economic factors are reflected inOregon- 

 Washington landing statistics, it inay be that 

 annual variations in sea temperatures are affect- 

 ing the success of the fishery by varying avail- 

 ability to the fishermen. 



The latitudinal abundance of albacore in 

 the equatorial Pacific, determined from catch 

 statistics, was not related to the amount of food 

 eaten by albacore captured in this area. During 

 the summer in the temperate North Pacific, fish 

 with high volumes of stomach contents were 

 found south of successive peak volumes of organ- 

 isms captured by midwater trawls and zooplank- 

 ton nets. This suggests successive trophic levels 

 associated with an advancing oceanographic and 

 biological "frontier" in the Transition Zone. In 

 the equatorial Pacific, fish with highest volumes 

 of stomach contents were found to the west, while 

 in the temperate North Pacific , stomach content 



Relations between sea surface tempera- 

 tures and landings were investigated for the 

 years 1947-60. In years of above normal tem- 

 peratures, landings were, in general, signifi- 

 cantly greater than in years of below normal 

 temperatures. Whereas warm water did not 

 insure a good fishery, widespread cold water 

 was detrimental to the success of the fishery. 

 The data suggest that in June, if the sea temper - 

 ature anomaly is large enough, it is possible to 

 predict whether or not sea temperatures will be 

 favorable for albacore at normal time of com- 

 mencement of the fishery in mid-July. 



